UPK Explorer mesh import writeup
Tutorial for UPK Explorer for UE2 - UE3
This only covers Bioshock Infinite Elizabeth model, but is hopefully helpful for all UPK Explorer modding too.
I recommend exporting really complex model edits like Elizabeth into 2 seperate mod folders, a mesh pack and a texture pack, it's less strain on the game package editing from what I have heard.
First of all load the game into UPK Explorer and find the mesh. Click the .fbx button to download it as a fbx. Make a designated folder on your computer for exported meshes because it will export the diffuse texture as well.
Also note that this mesh is seen in one 'package'. This is important for knowing where to import the model into later.
I know it is possible to do a big override of an entire model gamewise, never did this myself yet, but that is better for props. For a complex model like Elizabeth it's better to do things 1 package at a time.
Now load the fbx into Blender and do your edits.
I did my edits in Blender 3.6. I think this may be the only Blender version that's supported currently, but don't quote me on that + it may get updates later. So always check most recent UPK Explorer documentation and wiki.
Once done export it with the approved settings. I like to save these settings as a FBX export preset so there's no room for human error. As of writing the approved settings are these
Now we go back to UPK Explorer, change tabs and look up the package.
We now can import our own mesh!
It will import in sideways
Repeat as necessary for however many packages the mesh appears in.
Once you are done, click Create Game Patch. It will create a folder called MyMod. Rename this something memorable and then put it aside because it's done. If you ever want to edit your finished game patch, you can rename it to MyMod and the UPK will know to reload it when you open the Explorer.
Remember scale. The armature imports in at a different scale than the model which can easily trip you up. Check both in blender under Object tab.
It's wise to turn on 'show axes' and 'show bones' . You want it to look the same as the model you replaced.
Above is right. Below is very wrong.
If the mesh has more than 1 UV map listed, delete the second one, even if it imported in with it. Or you'll get weird normals on the skin. (Although, this may be a quirk of the Elizabeth model, I am not sure if it applies to other models)
Physics-enabled meshes need to remain the same completely, as far as I can tell from my experiments. You can generally tell if a mat is physics enabled because it has its own material listing.
I am informed that you want to delete the skirt or the hair, you need to make the texture entirely black on the diffuse (#fffff renders as transparent in the engine) so it's still technically there but not visible. I haven't tried it yet but that works apparently.
Seen here the Finkton Elizabeth model, where all the physics meshes have their own seperate material entry.
Extra entries for her ponytail, her scarf, and her skirt.
The corset outfit has skirt+hair physics chunks, I think it's the same for the Burial At Sea ones though I've never tried editing her hair there.
Keep the material order list the same, it will make your life easier. I think it is possible to juggle these around in UPK but why make your life any more difficult if you have 9+ versions of the mesh to import?
Mesh weights need to be quantized. There's a well hidden auto-quantize option in Blender somewhere if you need to make edits to weights, which is a lighter touch than running the quantize operation in the Weight Paint menu.
Things with different assigned materials need to be seperate chunks and not attached at a vert level. This is more a theory than proven, but it makes sense to me with how the models import.
Again a theory, but I think there's only a certain amount of weight influences a certain material can have each- this would at least explain why some of the Elizabeth models have 2 'skin' materials applied with no seeming reason as to why. (Why do I think this ? One of meshes with extra skin was glitching, I assigned more of the mesh to the second skin entry and it was fixed. )
There's not a lot of point saying much about texture pack creation, because it's pretty self explanatory and there's already a good video tutorial floating around.
But basically: drop your newtexture.dds into the pre-generated 'Import' folders, with the correct file format and name. (just like how they exported out.) If your new texture is not eligible to be imported, it will throw an error or just won't show up. Click create texture pack at the bottom of the screen, and it will create a MyMod folder for you to rename. Then it’s ready to test in the game.
If you click create texture pack while your mesh mod is still called MyMod, it will add textures to your mod in progress instead of making a MyMod2 folder. Which may be good or bad, depending on if you did it on purpose or not.
All the file formats I used modding Infinite were possible to export with GIMP.
That is basically all I know so far about editing these kinds of meshes. If you have any further issues, most information is on the official 'Mod Creators Guild' discord or some other modding discord.
